Junio C Hamano [off-list ref] writes:

So, here is a two-patch series that tries to do so, primarily done
to gauge if there still is the level of interest needed to make it
worth for us to pursue this topic.  Here is the first one; I'll send
the second one that takes advantage of this change separately (but
it should be trivial to imagine what that step would involve).

-- >8 --
Subject: [PATCH 1/2] send-email: update the mechanism to set default configuration values

The program has a good mechanism to specify the fallback default
values for boolean configuration variables after two invocations of
read_config() for "sendmail.$ident.$var" and "sendemail.$var" have
not found any configuration.  Imitate it so that we can set the
default values for non-boolean variables as well.

Signed-off-by: Junio C Hamano <redacted>
---
 git-send-email.perl | 51 ++++++++++++++++++++++++++-------------------
 1 file changed, 29 insertions(+), 22 deletions(-)

This one was embarrassingly buggy, and needs the following squashed
in.

Sorry about that.

 git-send-email.perl | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/git-send-email.perl b/git-send-email.perl
index ca7faff094..831947c7ed 100755
--- a/git-send-email.perl
+++ b/git-send-email.perl

@@ -411,7 +411,7 @@ sub read_config {
 	}
 
 	foreach my $setting (keys %config_settings) {
-		my $target = $config_settings{$setting};
+		my $target = $config_settings{$setting}->[0];
 		next if $setting eq "to" and defined $no_to;
 		next if $setting eq "cc" and defined $no_cc;
 		next if $setting eq "bcc" and defined $no_bcc;

@@ -447,10 +447,13 @@ sub read_config {
 }
 
 # fall back to builtin defaults
-for my $setting (values %config_settings) {
-	if (@$setting == 2 && !defined (${$setting->[0]})) {
-		${$setting->[0]} = $setting->[1];
-	}
+while (my ($name, $setting) = each %config_settings) {
+	next unless @$setting == 2;
+
+	my ($target, $default) = @$setting;
+	if (ref($target) eq "SCALAR") {
+		$$target = $default unless defined $target;
+	} # elsif ... for other types later.
 }
 
 # 'default' encryption is none -- this only prevents a warning